The present invention relates to connectors for printed circuits and the like. In particular, it relates to connectors formed individually by the assembly of blocks of insulating material and contacts into such assemblies which may readily be shortened, either before or after completion of their assembly, to eliminate undesired lengths of connectors and provide a desired number of contacts only.
There is a pseudo standard for the dimensions of these connectors which has been established by common use in addition to the dimensions specified under United States military specification MIL-C-21097. These standard dimensions relate to:
Card insertion depth PA0 Overall height of connector PA0 Card slot width PA0 Distance between mounting centres.
This pseudo standard can be readily assessed by compiling a chart of dimensions from 10 to 20 of the world's leading connector manufacturers. All these dimensions however relate to connector bodies moulded in one piece.
This type of prior art connector having therefore been provided in sizes to include fixed numbers of contacts depending on the contact pitch. E.g., for a pitch of 3.96 mm. standard connector lengths are 6, 10, 15, 18, 22, 28, 36 and 43. When there has been a need for more contacts than are in a standard unit but fewer in the next larger size, the next larger size has been used with a corresponding waste of contacts and the cluttering of space with unused parts.
Prior art connectors have been available only in dimensions which do not allow the connector to be fully compatible with the standard dimensions of the one piece moulding.
Prior art connectors have also required very close tolerances when being cut to length.
Prior art connectors have severe limitation in their variety of mounting provisions.
Attempts have been made to overcome these problems, however these attempts have not been completely successful.
Australian Patent No. 503,549 describes an electrical connector having five parts; the metal contacts, the body, a slide element made from insulating material which holds the contact elements in the body and two end feet which have teeth which mate into the contact cavities and lock the slide securely into the body of the connector.
However it has been found in practice that feet having no top clamping means are prone to work themselves loose or snap under certain conditions. If the end foot works itself loose from the body, not only does it run the risk of falling off but the tabs on the printed circuit board will certainly not line up with the contacts on the connector. Further, although connectors made under the above mentioned Australian Patent are able to meet the pseudo standard for card slot width and mounting hole dimensions, one of either connector height or card slot depth have to be sacrificed making the connector too high for many applications. Additionally cutting tolerances on this connector are exceedingly critical and the assembly time is far in excess and requires more equipment than the subject of this specification.
Another prior art connector is shown in German Patent No. 1,936,019. However, this suffers from the same disadvantage as the connector of the beforementioned Australian Patent, in that the tolerances of the components must be very exact to ensure adequate connection and as a result is prone to the end foot slipping loose. Another disadvantage is that the connector of the German Patent would not satisfy the height limitations required for standard connectors.
A further prior art connector is described in U.S. Pat. No. 3,131,016 in the name of A. B. Clewes. In the Clewes connector the two end contact position are lost as a projection from the foot slides into the end contact position to completely block them. Thus this solution has not been fully satisfactory.